Thermal Performance of a Flat Heat Pipe with Orthogonal Grooves for Cooling Electronic Components

In this experimental study, we evaluate the heat transfer performance of a flat copper heat pipe filled with water incorporating a capillary structure composed of cubic orthogonal grooves (Flat Orthogonally Grooved Heat Pipe, FOGHP). Under a cold source temperature equal to 40 ℃, it is shown that the FOGHP dissipates heat input powers up to 60 W, which corresponds to a heat flux of nearly 10 W/cm2 with evaporator temperatures lower than 100 ℃ for the horizontal and thermosyphon orientations, and 110 ℃ for the anti-gravity orientation. The effective thermal conductivity of the FOGHP reaches 2.6, 2.8, and 2.2 times that of copper for the horizontal, thermosyphon, and antigravity positions respectively. Compared to a flat copper plate, the FOGHP allows reductions in the maximum evaporator temperature of 58 ℃, 63 ℃, and 51 ℃ for the horizontal, thermosyphon, and anti-gravity orientations, respectively. The capillary limit is found to be 30 W whatever the FOGHP orientation, and the evaporation heat transfer coefficients are higher than those of condensation.